Impact of Osmotic Dehydration on the Physical, Mechanical, and Textural Properties of Paneer From Different Milk Sources

This study evaluates the effects of osmotic dehydration (OD) on the physical, mechanical, and textural properties of paneer made from buffalo, cow, and full-cream milk. Paneer slices were pre-treated at 4°C with four different concentrations of salt solution for 12 h at an osmotic solution-to-product ratio of 1:4 (w/w). Following pre-treatment, the samples were dried in a tray dryer at 50°C. The full-cream milk paneer was found to have the highest moisture content compared to other paneer varieties due to the homogenization process. The overall dimensional properties of OD-treated paneer, including average length, width, thickness, geometric mean diameter, surface area, and volume, ranged from 0.0174 to 0.0196 m, 0.0164 to 0.0186 m, 0.004 to 0.0054 m, 0.0108 to 0.0121 m, 0.34 × 10⁻³ to 0.464 × 10⁻³ m², and 11.71 × 10⁻⁷ to 17.991 × 10⁻⁷ m³, respectively. The highest sphericity value of 0.6656 was noted in 12% OD-treated full-cream milk paneer. Bulk and true density increased non-linearly, while porosity decreased linearly with a reduction in moisture content from 12.46% to 9.25% (w.b) in buffalo milk samples. Untreated full-cream milk paneer exhibited the lowest angle of repose (29.89°) and volume shrinkage (19.82%) with an 8.37% decrease in moisture (w.b). Osmotic dehydration was found to have a favorable effect on the weights of 10, 50, and 100-paneer slice samples in buffalo milk, while cow milk paneer with higher solute concentration exhibited the highest rehydration ratio of 1.89. The OD-treated paneer sample with 12% concentration from cow milk exhibited a higher volume shrinkage value of 37.84%. The OD-treated paneer with a solute concentration of 3% from cow and buffalo milk was found to have the highest volume expansion of 60.25% and 88.81%, respectively, at room temperature. Regarding external friction coefficients, the highest value was observed for aluminum plates (0.59) in full-cream milk paneer, followed by galvanized iron (0.52) and stainless steel (0.42) in buffalo milk paneer. Paneer prepared from buffalo milk with a 3% solute concentration showed a significant decrease in hardness value to 393.56 N.